Nine over-crossings along Interstate 80 will be retrofitted to meet new clearance standards -- which makes some foothills residents nervous about traffic congestion as the Caltrans project gets underway.

The cost of the project is around $36 million, according to the state's transportation department.

Six of the over-crossings will be raised -- in some cases almost 2 feet -- and on the other three over-crossings, the freeway will have to be lowered.

Caltrans said construction crews will work on one crossing at a time, and it estimates freeway closures of one to two nights per crossing.

People who use the crossing everyday, such as Lisa Robinson, are concerned about the detours.

"It’s a huge impact on me," Robinson said. "I use (Horseshoe Bar Road) four times a day. It’s going to take me 20 minutes longer to get there and back home."

Other drivers are worried about the impacts on schools.

"There are two elementary schools that way," said Kevin Ash, who lives on the east side of I-80 and uses Horseshoe Bar Road to get to work at Del Oro High School. "So, you could have parents going that way to drop off their little ones and others coming this way for the high schools."

Caltrans will post detours for local and freeway traffic.

The project is expected to start in late May or early June and end in the fall of 2015.